Thermo and pH Sensitive Copolymer Based on Acrylic Acid and N-Isopropylacrylamide Grafted onto Polypropylene

Abstract

Binary graft copolymerization of pH sensitive of acrylic acid (AAc) and thermosensitive N-isopropylacrylamide (NIPAAm) monomers onto polypropylene films (PP), was carried out by two step method, and their pH and thermal sensitivity were studied. Graft polymerization of AAc onto PP was carried out by a pre-irradiation oxidative method using a 60Co gamma radiation source (Gammabeam 651-PT, Nordion International Inc.) NIPAAm was grafted onto PP-g-AAc a second step. The influence of synthesis conditions, such as pre-irradiation dose, reaction time, monomer concentration, and reaction temperature was studied. The PP samples grafted with the binary monomers were characterized with thermogravimetric analysis and differential scanning calorimetry. The lower critical solution temperature (LCST) and pH critical were obtained by swelling and water contact angle determinaions.